This invention relates to seating furniture, and more particularly to an arrangement for pivotably mounting a back to a seat in a chair or other seating furniture arrangement.
Various arrangements are known for providing pivoting movement of a chair back relative to a seat. One example is illustrated in Ambasz U.S. Pat. No. 4,084,850, which discloses a sleeve mounted to each side of a chair back and the upper end of a rod pivotably engaged with the lower end of the sleeve. The rod extends through a passage defined by a cylindrical retainer engaged with the seat, or with an upright extending upwardly from the seat. The rod defines an enlarged lower end, and a spring bears between the lower end of the rod and the lower end of the cylindrical retainer. Pivoting movement of the back causes the rod to move upwardly relative to the cylindrical retainer and functions to compress the spring, such that the spring resists rearward movement of the chair back and provides forward pressure on the user""s back. While this type of arrangement has been found to operate satisfactorily, it involves a number of components which must be assembled together in order to effectuate pivotable mounting of the back to the seat.
The ""850 patent illustrates other alternative arrangements, including a lever arm extending downwardly from the seat into a passage defined by an upright seat mounting section, with a resilient compressible member being engageable with the lever arm. This arrangement provides compression of the resilient member as the seat is pivoted rearwardly, which resists such rearward movement and provides a forward bias to the back.
It is an object of the present invention to provide a simplified back pivot arrangement for a chair, which reduces the number of parts and assembly steps required to mount the back to the chair, and which provides satisfactory pivoting movement of the back relative to the seat. It is another object of the invention to provide such a back pivot arrangement which is capable of providing progressively increasing resistance during rearward pivoting movement of the back relative to the seat. It is a further object of the invention to provide such a back mounting arrangement which limits pivoting movement of the back relative to the seat without contact between the back and the seat. A still further object of the invention is to provide such a back mounting arrangement which is extremely simple in its components and their construction and assembly, yet which provides highly satisfactory pivoting movement and resistance of the back relative to the seat.
In accordance with the invention, seating furniture such as a chair includes a seat member and a back member, which are formed with facing open pockets or passages. A flexible bar-type pivot member includes a lower section adapted to be received within the seat member passage and an upper section adapted to be received within the back member passage. The seat member and the back member define facing surfaces which are spaced apart from each other, and an intermediate portion of the pivot member is located within the space and between the upper and lower sections of the pivot member. A limit member, which may be in the form of a limit strap, is engaged with the pivot member for limiting rearward movement of the back member relative to the seat member.
The upper and lower ends of the pivot member are fixed relative to the back member and the seat member, respectively. When the back member is in its at-rest position, a gap is defined between the upper section of the pivot member and the rear surface of the back member passage, and a gap is also defined between the lower section of the pivot member and the rear surface of the seat member passage. With this arrangement, the pivot member initially flexes rearwardly to engage the pivot member with the upper end of the seat member passage when initial rearward pressure is applied to the back member. Additional rearward pressure causes engagement of the pivot member with the lower end of the back member passage. Thereafter, resistance to rearward pivoting movement is provided by the intermediate section of the pivot member, which is configured and has a thickness which provides a relatively high degree of resistance.
The limit member overlies the pivot member, and is operable to control the range of movement of the back member relative to the seat member. The limit member and the pivot member define cooperating engagement structure, which is operable to prevent additional bending of the pivot member when the back member has attained a predetermined angular position relative to the seat member. Representatively, the pivot member is provided with upper and lower protrusions which extend from a front surface of the pivot member. The limit member has spaced apart openings which receive the pivot member protrusions, and one or both of the limit strap openings are slightly larger than the pivot member protrusions. During pivoting movement of the back member; the front of the pivot member becomes slightly elongated and the back of the pivot member becomes slightly compressed. In this manner, the limit member opening engages the pivot member protrusion when the back member is pivoted to a predetermined angle relative to the seat member, to prevent further bending of the pivot member and thereby to limit movement of the back member relative to the seat member. When rearward pressure on the back member is relieved, the resiliency of the pivot member and the limit member function to return the back member to its original position.
Various other features, objects and advantages will be made apparent from the following detailed description taken together with the drawings.